ABO-incompatible bone marrow transplantation: preparation by plasma exchange and in vivo antibody absorption

Adsorption of chain type-specific ABO antibodies on Sepharose-linked A and B tetrasaccharides

BACKGROUND

Antigen-specific removal of anti-A and anti-B on immunoadsorption columns carrying the blood group A and B trisaccharides is one important component of some protocols used in ABO-incompatible organ transplantation. Because ABO antibodies exist requiring parts of the core saccharide chain for binding, the anti-A and -B-binding capacity of individual and combined, Sepharose-linked Types 1 through 4 A and B tetrasaccharides with that of the A and B trisaccharides was compared.

STUDY DESIGN AND METHODS

Sepharose-linked A and B tri- and tetrasaccharides were used to adsorb anti-A and -B from pooled blood group O serum. Remaining chain type-specific anti-A and -B were detected and quantified in enzyme-linked immunosorbent assays using wells coated with neoglycoproteins or recombinant mucins carrying A and B determinants on defined core saccharide chains.

RESULTS

Significantly more anti-A Type 3- and 4-specific immunoglobulin (Ig)G remained after adsorption on the A trisaccharide and the A Type 1 and A Type 2 tetrasaccharide than after adsorption on the A Types 3 and 4 tetrasaccharides. Selective adsorption of chain type-specific IgG anti-B was detected on Sepharose-linked B tetrasaccharides. In contrast, there were no chain type-specific IgM anti-A or -B. A combination of the A or B tetrasaccharides adsorbed a larger fraction of the IgG anti-A and -B repertoires than the corresponding trisaccharides.

CONCLUSION

There are chain type-specific anti-A and anti-B IgG, and an adsorber based on a combination of Types 1 through 4 A or B tetrasaccharides will be a more efficient adsorber than an adsorber based on the A or B trisaccharides.

In vitro assessment of a new ABO immunosorbent with synthetic carbohydrates attached to sepharose

Transplantation across the ABO barrier is sometimes done in cases of emergency, such as acute liver failure, but is also carried out in elective cases, e.g. kidneys from living donors. Reducing the recipient anti-A/B antibody titres is often necessary in ABO-incompatible kidney transplantation. This is usually done by the use of techniques such as plasmapheresis and protein A- or sepharose-linked anti-human Ig immunoadsorption. A new ABO immunosorbent with synthetic A- or B-trisaccharide carbohydrate epitopes linked to a sepharose matrix has been tested. Columns made of this material have been tested in vitro with plasma from A- and B-individuals, assessed for antibody reduction capacity, flow characteristics, biocompatibility, and unspecific protein adsorption. The columns have a high capacity for ABO antibody removal, reducing titres by three to seven steps in one passage. We noted a high biocompatibility, with no unspecific protein adsorption, no activation of coagulation factors, and a low activation of complement, no immune complex formation and no cytotoxicity towards cultured mammalian L929 cells.

A simple technique for red blood cell removal in major ABO-incompatible bone marrow transplantation

A simple technique for red blood cell (RBC) removal in major ABO-incompatible bone marrow transplantation is reported requiring two centrifugation steps, special blood bags and a mechanical device to separate the buffy coat from RBCs within the bag. In 42 transplantations an average of 84% of nucleated cells was recovered with an average contamination of 7.5 ml packed RBCs. The preparations were well tolerated in all patients whose isoagglutinin titers had not been reduced. Bone marrow engraftment was not significantly different from control groups.

Hematopoietic stem cell processing and storage

The techniques to collect, process, and store HSC in anticipation of transplantation are now widely available. Important unresolved issues revolve around the as yet imperfect identification and classification of totipotential progenitors. However, much progress has been and will continue to be made despite this limitation. Research priorities of present and future stem cell processing laboratories should include: 1. Optimization of liquid (nonfrozen) storage techniques. This will permit more complex cell-specific manipulations, such as T-lymphocyte subset selection, isolation of CD34+ populations, treatment in vitro with growth factors, gene transfer experiments, and long-range transport of HSC, to be performed while preserving HSC integrity. 2. A better understanding of the regulation and kinetics of peripheral blood and umbilical cord HSC, to allow optimum collection procedures that do not require marrow harvesting. 3. An intensive study into the optimum conditions of collection, processing, and storage of megakaryocytic progenitors to decrease the long platelet-transfusion dependency of the myeloablated patient. 4. A search for a simple in vitro correlate of engraftment potential of a stem cell preparation. This will greatly improve the quality control functions of the laboratory as well as contribute to better patient selection for transplantation.

Transplantation of major ABO-incompatible bone marrow depleted of red cells by hydroxyethyl starch

23 bone marrow transplant recipients whose donors where major ABO-incompatible received marrow depleted of red cells prior to infusion utilizing gravity sedimentation in hydroxyethyl starch. The in vitro red cell-depletion procedure effectively removed 97.8% (mean) of the red cells from the harvested marrows and preserved 86.8% of the nucleated cells and 98.2% of the CFU-C activity in 25.4% of the original volume. All recipients had a significant quantity of isohemagglutinins of both IgM and IgG classes demonstrable in their serum at the time of the marrow infusion. Patients were premedicated and well-hydrated prior to the infusion and tolerated the infusion well. These patients demonstrated bone marrow engraftment at the same rate as did those patients whose marrow donors were either ABO-identical or minor ABO-incompatible. There was no difference in the incidence of or time to development of graft versus host disease, the incidence of graft rejection, or patient survival among the groups. Recipients of red cell-depleted major ABO-incompatible bone marrow transplants demonstrated production of donor-type red cells somewhat later and required slightly more red cell transfusion support that did the other groups of recipients. This red cell-depletion technique is safe and effective in the management of major ABO-incompatible bone marrow transplantation.

ABH incompatible bone marrow transplantation: removal of erythrocytes by starch sedimentation

Nineteen patients with acute leukaemia underwent bone marrow transplantation despite major ABH incompatibility between donor and recipient. The marrow inoculum was prepared prior to infusion by admixture with hydroxyethyl starch to sediment the incompatible erythrocytes, which were then discarded. The infusion was well tolerated with two patients developing transient haemoglobinuria, seven patients developing low grade fever and 10 experiencing no reaction. Durable haematopoietic engraftment was achieved in the 18 evaluable patients and was not influenced by pre-transplant isohaemagglutinin titres. No difference in time to engraftment, incidence of GVHD or in overall survival was found, compared to ABH compatible transplants. Therefore, the presence of incompatibility did not appear to influence transplant outcome adversely. The technique described is a rapid and safe method for overcoming the ABH barrier in marrow transplantation.

Severe delayed hemolytic transfusion reaction complicating an ABO-incompatible bone marrow transplantation

A 26-year-old, blood group O bone marrow transplant recipient experienced a severe, delayed hemolytic transfusion reaction 6 days following transplantation of marrow from his HLA-mixed lymphocyte culture - identical, blood group AB sister. The patient's pretransplant serum contained both anti-A (IgG titer = 1:128; IgM = 1:32) and anti-B (IgG = 1:16; IgM = 1:64) which was reduced by a two-plasma volume plasma exchange followed by transfusion of four units of incompatible, donor type red cells. The patient experienced no immediate adverse reaction. On the 6th posttransplant day, he became acutely dyspneic. His hematocrit dropped to 18%; the direct antiglobulin test was positive for IgG and complement; anti-A and anti-B were eluted from his red cells. His peripheral blood smear demonstrated extensive agglutination resembling a mixed field reaction. This case demonstrates that significant morbidity may be associated with major ABO-incompatible bone marrow transplantation, that the transfusion of incompatible red cells should be undertaken with extreme caution, and that efforts should be continued to develop methods of pretransplant in vitro red cell removal from the infused bone marrow.

Transfusion of patients undergoing bone marrow transplantation

Bone marrow transplant recipients require intensive transfusion support preceding the marrow infusion, because of their underlying disease or the chemotherapeutic agents administered, and for 14 days or more post-transplantation until engraftment has occurred and marrow function has returned. Red blood cells, plasma, and platelets are the usual components transfused; granulocyte concentrates are occasionally required. Marrow transplantation across ABO and Rh barriers is performed routinely and requires careful, knowledgeable attention to the blood group of components chosen throughout the transplantation process to ensure effective transfusion support. This paper is a review of the general principles governing pre- and post-transplantation transfusion support, potential indications for the transfusion of various blood components in the marrow transplant setting, and the recommended blood groups of these components when ABO incompatibilities exist.

ABO-incompatible bone-marrow transplantation: removal of red blood cells from donor marrow avoiding recipient antibody depletion

Eight patients with acute leukaemia undergoing allogeneic bone-marrow transplantation from ABO-incompatible donors received red-cell-depleted donor marrow without any procedure to diminish their anti-ABO antibody titres. Successful marrow red-cell removal (mean 98.8%) was achieved by means of a large-volume separation technique on Ficoll-Metrizoate in the IBM 2991 blood-cell processor. Clinically significant ABO-haemolytic reaction was prevented in all patients, and there was neither failure of engraftment nor rejection. This approach used alone is satisfactory for most ABO-incompatible marrow-transplant recipients, although combining this with some method of recipient antibody depletion, such as plasma exchange, is recommended in the occasional patient with high anti-ABO titres.